DE102004015298B3 - Gas filter for automotive air bag gas is fabricated from knitted mass of round wire subsequently flattened and pressed in a form - Google Patents

Abstract

A filter for an airbag filling gas, which is arranged in the flow path for the filling gas generated by a gas generator 1 to the airbag, with a flow cross-section filling metal wire mesh 3 as a filter body, wherein the metal wire mesh 3 is formed of a flat wire.

Description

The The invention relates to a filter for an airbag filling gas the preamble of claim 1.

In such an off DE 44 44 490 A1 known filter consists of the filter body made of metal spiral wool, in which individual spiral turns are hooked together and the spiral turns are formed from a long span with an approximately rectangular cross-section.

Out DE 10 51 249 A is a liquid filter with plate-shaped filter bodies known. To produce the respective dish-shaped filter body is based on a round wire, which is deformed into a flat wire and wound with closely superposed turns to a disc, which is then bent into the plate shape.

Out EP 1 074 433 A2 is a filter in an airbag inflator known, the filter body made of flat braids processed round wires with a diameter of 0.3 to 0.6 mm. The flat braids are arranged around a cylindrical body of the gas generator and compressed to a density of 3.0 to 5.0 g / cm ³ .

Filters, which off DE 198 05 127 C1 are known, include as a filter body wire mesh, wire mesh or knitted wire, which are made of round wires.

Out round wires formed filter body can be easily made by braiding, weaving or knitting, however, such filter bodies have only a limited surface area.

Out DE 689 21 302 T2 ( EP 0 370 734 B1 ) it is known to produce the filter body by winding a wave-shaped wire and to compress it into an annular or hollow cylindrical shaped body.

task The invention is to provide a filter of the type mentioned, which improved at the same wire mass and ease of manufacture Has filter effect.

These The object is achieved by the Characteristics of claim 1 solved.

Of the is formed from the metal wire knit of the flat wire filter body as pressed molded body formed and has in particular the shape of a hollow cylinder, a Ringes or a disc. The final shape of the filter body depends on the formation of the flow path along which the filling gas formed by the gas generator the airbag interior is passed.

Of the Flat wire has the same mass a larger surface than a round wire. From this results an improved cooling effect on the guided through the filter airbag filling gas, as an improved heat dissipation is reached. In addition, will by the disordered alignment of the flat surfaces of the flat wire in the filter body the Cleaning effect of the filter increases, wherein during compression of the filter body the irregular arrangement the flat sides of the flat wire in the filter body is still increased. Before geous enough, therefore, with reduced wire mass the same Filter effect as with round wires be achieved.

Of the Flat wire is by flattening made of a round wire. This is a round wire with a Diameter of about 0.5 mm to 0.8 mm to a thickness of the flat wire flattened, which corresponds to about 40% to 60% of the round wire diameter. One so flattened Wire is rounded on the narrow sides, so that the knitting process for Production of the wire knit roll is not affected. The flat wire can also consist of a drawn flat wire, as far as it is designed so that it becomes a knitted wire can be processed.

The wire knit roll may be a wound wound from a flat knit bobbin. Preferably, the wire knit roll is formed as a single or multi-layer circular knit. The rolling is then pressed to the final molded body, in particular hollow cylindrical or annular shaped body. The pressed molding preferably has a density between 0.8 to 5.0 g / cm ³ . Within a derarti gene density range ensures that the filter body exerts the necessary cooling effect and cleaning effect with sufficient gas permeability.

Based the figures is based on an embodiment the invention even closer explained. It shows:

1 a sectional representation of an embodiment;

2 a side view and a cross section of a flat wire from which the wire mesh for the filter is produced and

3 in a perspective view of a pressed hollow cylindrical molded body, which forms the filter body in the embodiment.

The 1 shows a schematic representation of a longitudinal section of a filter 2 , which is arranged in the flow path of an Airbagfüllgases. The airbag filling gas is generated pyrotechnically by a gas generator, for example. The filling gas moves out of the gas generator 1 through gas-permeable partitions 6 in the interior of the hollow cylindrical filter body, which consists of a wire knit molding 3 consists. The hot and laden with particles airbag filling gas moves through the wire knit molding 3 and passes through diffuser openings 4 in the housing directly or via a further gas guide in the interior to be filled interior of the airbag, not shown.

In the filter 2 takes place via the wire knit molding 3 by heat dissipation cooling of the filling gas and retention of the particles, which is in the from the gas generator 1 coming filling gas are still located. This ensures that through the diffuser openings 4 a purified and cooled gas is forwarded to the airbag.

In the illustrated embodiment, the wire mesh molded body 3 from one or more flat wires 5 educated. The respective flat wire 5 is designed as a flat flat wire. Such a flat wire is brought by flattening a round wire in the flat wire form. The starting material of the round wire has for this purpose preferably a diameter of 0.5 to 0.8 mm and is on a thick d ( 2 B ), which is flattened to about 40% of the diameter at the smaller diameters and to about 60% of the starting diameter at the higher diameters. As seen from the sectional representation of 2 B) can be seen, keep the narrow sides of the flat wire 5 a rounded shape, so that the knitting process is not affected by the cross-sectional shape of the flat wire. The 2 (A) shows the flat wire 5 in side view.

The metal wire knit, which is a wound flat knit or preferably a circular knit, becomes that in the 3 illustrated wire mesh molded body 3 , which forms the filter body, pressed. In this case, the flat sides of the flat wire get 5 an irregular arrangement in the wire knit molding 3 , Due to the increased turbulence, which is erriecht here, one achieves an improved heat dissipation from the passed through Airbagfüllgas and increased cleaning effect due to the increased surface.

1

inflator

2

filter

3

Wire mesh molded body (filter body)

4

diffuser openings

5

flat wire

6

partitions

Claims (3)

Filter for an airbag filling gas with a flow cross-section of the filling gas filling filter body of a flat wire, characterized in that the filter body of a Metalldrahtgestrick ( 3 ) of the flat wire ( 5 ) is formed and the flat wire ( 5 ) is formed from a round wire with a diameter of 0.5 mm to 0.8 mm, which is flattened to a thickness which corresponds to about 40% to 60 of the round wire diameter and that the metal wire knit ( 3 ) is pressed into a shaped body. Filter according to claim 1, characterized in that the molded body is designed as a hollow cylinder, ring or disc. Filter according to claim 1 or 2, characterized in that the density of the shaped body is 0.8 g / cm ³ to 5.0 g / cm ³ .